1. Field of the Invention
The present invention relates to an image recording device and a method for controlling the image recording device.
2. Description of the Related Art
Generally, an image recording device represented by a printer and a copying machine conveys a record medium, and records an image during the conveyance. For example, in the image forming device in the ink jet system, ink is jetted from the head nozzle of the ink head to the medium (for example, printer paper) conveyed by the conveying unit such as a platen etc. to record an image (recording process).
When an image is recorded, although a fed medium is displaced in the direction (main scanning direction) orthogonal to the direction of conveyance (subscanning direction), the ink is not jetted to the conveying system exposed outside the medium as spots. Therefore, the position of the side end portion of the medium is to be correctly detected.
To detect a side end portion, an image sensor, an optical line sensor, etc. are generally used. In the detection using such a light receiving element, the end position of a medium is determined by the level difference of the reflected light from the medium and the member (for example, a conveying belt) which supports the medium.
For example, the patent document 1 discloses the end position detecting method for emitting light to recording paper and detecting the end position of the recording paper based on the quantity of light reflected from the recording paper. The method includes: a step of storing the quantity of reflected light from a recording paper guide device; a step of advancing the recording paper to detect the quantity of reflected light of the recording paper, and calculating the difference from the quantity of reflected light of the medium guide device; a step of multiplying the difference by a value of C exceeding 0 and smaller than 1 to set a reference level; a step of returning the recording paper to the downstream at the position where the reflected light of the recording paper guide device can be detected; and the step of determining that the starting point of the recording paper has reached the reference position at the point where the quantity of reflected light has reached the reference level after advancing the recording paper.    [Patent Document 1] Japanese Laid-open Patent Publication No. 09-136741